3rd Draft

Transcript

Announcer: Busch Series racing On Fox!

Plaz: Special Physics Report by Michael Plasmeier, sponsored by ThePlaz.com

As the cars race around the track, the first law you will notice is Newton’s Third Law of motion. That forces always occur in pairs, an action and reaction force. Newton’s Third Law states that “Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object.” You can see that in racing as the racecar tires push backwards against the road, and the road pushes back on the tires causing the car to go forward. Friction is also necessary in this re-, in this operation, or else the racecar will not move.

You might wonder why if the forces are equal and opposite, why the road doesn’t move instead of the race car. The answer is because the road is connected to the earth, which has an extremely large amount of mass. The race car, comparatively so, has much less mass, therefore has much more acceleration when the same amount of force is applied to it.

The next physics property you can notice is centripetal acceleration. Did you know that race cars hafta push out against the track while cornering? You see, the tendency of an object is to continue in a straight line. If an object, like a race car, wants to curve, it must push inward. That push is a force and causes acceleration. Therefore it’s centripetal acceleration. That means that it’s center-seeking.

This force is provided by what else but our old friend, friction! Again, without enough friction the car could not turn or corner. If friction was magically turned off while a race car is turning, then the car would stop curving and move in a straight line tangent to the circle. Tangent means that it goes away from the center. Because of inertia, the car will continue moving in that straight line path indefinitely; it can not speed up or slow down.

Announcer: Looks like a nightmare. <Flashback sound effect> What happened here buddy? Hit the curb, hit the curb! The same place---

Plaz: Bam! That was a good crash! I don't know about you but that is what I watch the races for. Crashes are a good opportunity to see momentum in action. Momentum is the object's mass times its velocity. Momentum can also be called "inertia in motion." When momentum changes, that's called an impulse. An impulse is the force times the time that force is app- applied for. So a race car wants to increase the amount of time the force is applied for. So that means the force is less because it's spread out over a longer period of time. That is why the race car wants to hit tire walls, and not a solid brick wall.

There are many other physics principles that you can find by watching NASCAR. See you next time on physics talk with ThePlaz. <Ending music>